This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A303991 #16 Jan 07 2024 06:19:40
%S A303991 1,18,804,70980,10436805,2303750526,712510404592,294018013725192,
%T A303991 156070751204023425,103597044789173411410,84072367255899882570876,
%U A303991 81892130447332894817380044,94289343231845338982163322837,126676207083751543195799431746150,196394200592428254386554058525461440
%N A303991 Row sums of triangle A303990.
%H A303991 Seiichi Manyama, <a href="/A303991/b303991.txt">Table of n, a(n) for n = 1..214</a>
%F A303991 a(n) = Sum_{k=1..n} A303990(n, k) = Sum_{k=1..n} n^k * k^n, for n >= 1.
%F A303991 a(n) ~ n^(2*n). - _Vaclav Kotesovec_, Feb 09 2022
%t A303991 Total /@ Table[n^k k^n, {n, 15}, {k, n}] (* _Michael De Vlieger_, May 24 2018 *)
%o A303991 (PARI) a(n) = sum(k=1, n, n^k * k^n); \\ _Michel Marcus_, May 25 2018
%Y A303991 Cf. A303990, A368505.
%K A303991 nonn,easy
%O A303991 1,2
%A A303991 _Wolfdieter Lang_, May 22 2018